EXPERIENCE OF USING THE ANZI STRAIN CELL FOR STRESS CHANGE MONITORING - KEN MILLS, DAVE SELMO, JESSE PULLER, JIM SIMONOVKSIPublished Jan, 2015This Paper describes the ANZI (Australia, New Zealand Inflatable) strain cell and some examples of its application for stress change monitoring. The instrument has been used over the past three decades to measure three dimensional in situ stresses using the overcoring method of stress relief and monitor three dimensional stress changes in a range of applications mainly associated with underground coal mining, but also with civil and metalliferous mining projects.
The ANZI strain cell has a pressuremeter design that allow 18 electrical resistance strain gauges at various orientations to be pressure bonded directly to the rock on a borehole wall. The instrument's soft polyurethane membrane and hollow pressuremeter design have characteristics that facilitate deployment, enhance data gathering, and simplify analysis. Further recent developments that improve deployment and monitoring have increased the capability of the instrument. Automatic, remote, and high speed monitoring at resolutions of just a few microstrain has significantly improved the capability to measure and thereby understand the nature of changes in the three dimensional stress in rock strata around excavations in rock. EXPERIENCE-OF-USING-THE-ANZI-STRAIN-CELL-FOR-STRESS-CHANGE-MONITORING-KEN-MILLS-DAVE-SELMO-JESSE-PULLER-JIM-SIMONOVKSI-2015.pdf1.1 MB
ACG Deep Mining 2012 Stress Measurement Workshop - Ken MillsPublished Jan, 2012This paper describes the development of ANZI (Australia, New Zealand Inflatable) strain cell over the past three decades and the operation of the instrument including some examples of its application. The ANZI strain cell is used for measuring strain changes in rock on borehole walls suitable for estimating in situ stresses and stress changes. The instrument comprises a pressuremeter design that allows electrical resistance strain gauges to be pressure bonded directly to the rock on a borehole wall. The strain gauges are monitored during overcoring to obtain stress relief strains for estimation of the in situ stress. In monitoring applications, strain changes within a rock mass induced by mining and other construction activities are measured over time. ACG-Deep-Mining-2012-Stress-Measurement-Workshop-K.Mills-et-al-2012.pdf1.1 MB